Section 3 Rotor Survey & Approval
Clasification Society 2024 - Version 9.40
Clasifications Register Guidance Information - Guidance Notes For Flettner Rotor Approval, May 2015 - Chapter 1 Guidance Notes For Flettner Rotor Approval, May 2015 - Section 3 Rotor Survey & Approval

Section 3 Rotor Survey & Approval

Parent topic: Chapter 1 Guidance Notes For Flettner Rotor Approval, May 2015

3.1 General

3.1.1 The full process to be implemented for the Rotor Survey & Approval is given in Figure 1.3.1 Pictorial representation of Rotor Survey & Approval process. The relevant Sections are also highlighted.

Figure 1.3.1 Pictorial representation of Rotor Survey & Approval process

3.2 Concept

3.2.1  Risk Assessment. A risk assessment at the concept design stage is to be carried out with the aim of achieving the two safety objectives, which are described in Section Ch 1, 2.1 Objectives of Approval for Flettner Rotors. Such an assessment would generally be carried out by the party seeking the approval with or without support from LR and should be in accordance with LR’s ShipRight procedure for ARBD.

3.2.2  Approval in Principle. The risk assessment process aims to ensure that reasonably foreseeable hazards associated with any particular Flettner rotor design are identified and adequately controlled. After reviewing the completed risk assessment report, Approval in Principle (AiP) for the Flettner rotor can be issued subject to identified hazards being satisfactorily addressed.

3.3 Design

3.3.1 Mechanical Appraisal

  1. Required Submissions

    • Scoping study report (Stage 1 ARBD process)
    • Risk Assessment report (Stage 2 ARBD process)
    • Specification/requirements (Rotor inner and outer diameters, thickness, length, material, speed, etc.,)
    • Rotor design and drawings – Detailed breakdown
    • Calculated maximum actual thrust – All supporting calculations and assumptions
    • Details of the rotational drive system and bearing specification (Name of the manufacturer, maximum thrust load, etc.,)
    • Drawings and details of any hydraulic actuating mechanisms (Pipe design pressure, inner and outer diameters, thickness, material, design and working temperature, etc.,)
    • Information related to all the materials used for rotor construction
    • Factory Acceptance Test (FAT) schedule

  2. Applicable Rules (Existing)
    Provisional Rules for Sail-Assisted Ships, January 2008
    Rules and Regulations for the Classification of Ships:

    ShipRight procedure for ARBD

  3. Additional Verification
    Theoretical Maximum Thrust:

    • Verification of client’s thrust calculation
    • Thrust passed on to structures
    • First principle calculation

    The following formula may be used to calculate theoretical thrust (TFRT) produced by the Flettner rotor in Newton (N):

    TFRT = ρ x v x 2π x ωr2 x L

    where

    ρ = air density (kg/m3)
    v = maximum wind speed (m/s)
    ω = rotational speed (rad/s)
    r = rotor radius (m)
    L = length of the rotor (m)

    Bearing Loading Check:

    • Assessment of bearing specification for the loads applied

    General Design Analysis and Construction Review:

    • Access provisions for maintenance
    • Review of any application specific to safety considerations, e.g., personnel access during rotor operation

    Suitability for hazardous/explosive atmospheres.

  4. Deliverables
    The Design Appraisal Document (DAD) will be issued at the end of the design approval process.

3.3.2 Structural Appraisal

  1. Required Submissions

    • Scoping study report (Stage 1 ARBD process)
    • Risk Assessment report (Stage 2 ARBD process)
    • Specification/requirements (Rotor inner and outer diameters, thickness, length, material, speed, etc.,)
    • The intended service area
    • Finite Element Analysis (FEA) for structure
    • Plans and full particulars of the rotor systems showing materials and methods of construction and any secondary means of support
    • Supporting calculations in respect of the strength of the rotor systems
    • Thrust calculations

  2. Applicable Rules (Existing)
    LR Code for Lifting Appliances in a Marine Environment (LAME) (2013)

    Provisional Rules for Sail-Assisted Ships, January 2008

    Ch 1, 1.4 Structural arrangements 1.4.2 covers strength requirements for masts and posts. Strength must be adequate to resist highest design loading not less than that imposed by the sail system in the normal working conditions and emergency conditions.
    ShipRight procedure for ARBD

  3. Additional Verification
    Ch 4, 2.12 Wind loading – These requirements are valid for non-rotating conditions. In rotating conditions, the design calculations specific to the Magnus Effect are required to be submitted to LR’s Plan Appraisal Offices. The FAT and test program results are to be analysed by the designer, the local Surveyor and the Plan Appraisal Office.

  4. Deliverables
    The DAD will be issued at the end of the design approval process.

3.3.3 Electrotechnical Systems Appraisal

  1. Required Submissions
    Scoping study report (Stage 1 ARBD process) Risk Assessment report (Stage 2 ARBD process) Details of the safety systems which are to include:

    • Assurance case identifying safety critical elements of the system
    • Methodology and evidence for reducing the identified hazards in the Risk Assessment report to a tolerable level

    Details of control systems which are to include:

    • interfaces with ship's control, alarms and safety systems
    • description of operation with explanatory diagrams
    • line diagrams of control circuits
    • list of alerts and alarms and actions required by the operators
    • hardware certification details
    • software quality plans for software development
    • plans showing location and details of control stations

    Single line diagram of power system which is to include:

    • interfaces with ship's electrical systems
    • ratings of machines, transformers, batteries and semi-conductor converters
    • all feeders connected to the switchboards
    • section-boards and distribution boards
    • insulation type, size and current loadings of cables
    • make, type and rating of circuit-breakers and fuses

    FAT schedule

  2. Applicable Rules (Existing)
    Rules and Regulations for the Classification of Ships

    Provisional Rules for Sail-Assisted Ships (2008)

    ShipRight procedure for ARBD

  3. Additional Verification
    No additional requirements.

  4. Deliverables
    The DAD will be issued at the end of the design approval process.

3.4 Manufacturing

3.4.1  Survey & Inspection. The survey and inspection of the rotor during its construction are to ensure that the relevant Rule requirements stated in these Guidance Notes have been complied with and any conditions/recommendations given in DAD are addressed. It has to be conducted in accordance with Ch 1, 1.6 Survey requirements for sail systems of Provisional Rules for Sail-Assisted Ships, January 2008 andCh 12, 3 Survey requirements as applicable.

3.4.2  Testing. The FAT following rotor construction is to ensure that the relevant Rule requirements stated in these Guidance Notes have been complied with and any conditions/recommendations given in DAD are addressed. It also needs to be checked that the test schedule agreed with LR has been properly implemented. It has to be conducted in accordance with Ch 1, 1.6 Survey requirements for sail systems of Provisional Rules for Sail- Assisted Ships, January 2008 and Ch 12, 3 Survey requirements as applicable.

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